Stator construction for compressors



May 12, 1959' B. H. SHINN Original Filed Feb. 27, 1951 2 Sheets-Sheet 1May 12, 1959 B. H. SHINN 2,885,768

' STATOR CONSTRUCTION FOR COMPRESSORS Original Filed Feb. 27, 1951 2Sheets-Sheet 2 United States Patent 2,885,768 STATOR CONSTRUCTION FORCOIVIPRESSORS Byron H. Shinn, Bolton, Conn., assignor to United AircraftCorporation, East Hartford, Conn., a corporation of Delaware Originalapplication Serial No. 212,974, February 27, 1951. Divided and thisapplication February 26, 1953, Serial No. 339,089

7 Claims. (Cl. 29-156.4)

The present invention relates to axial flow compressors and particularlyto an arrangement for supporting the stator vanes in position. Thisapplication is a division of application Serial No. 212,974, filedFebruary 27, 1951, now Patent No. 2,749,026, for Stator Construction ForCompressors.

It has been customary to provide openings through the supporting shroudfor the vanes in which the vanes are positioned in assembly. Suchopenings are frequently provided by a punching operation. For a securefit of the vane within the opening in the shroud it is necessary thatthe punch conform almost exactly to the shape of the vane. Even then,however, the tolerances and variations in shape of both punch and vanemay result in openings which will not receive the vane, or which willnot securely hold the vane Without some looseness. A feature of thisinvention is the perforation of the shroud by the use of the vane itselfas the punch. The vane remains in position after the punching operationsuch that the resulting opening in the supporting shroud must ofnecessity conform exactly to the shape of the vane.

Where the shroud is box-shaped, as above mentioned, alignment of thepre-punched vane receiving openings in the inner and outer rings of theshroud presents a problem since a slight misalignment of the openingswould result in serious misalignment of the inner ends of the vanes. Afurther feature of the invention is the elimination of the alignmentproblems by the punching and assembly of the vanes and shrouds in asingle operation.

Other objects and advantages will be apparent from the specification andclaims, and from the accompanying drawings which illustrate anembodiment of the invention.

Fig. 1 is a longitudinal sectional view through a multistage axial flowcompressor with the vanes held by a box-type shroud.

Fig. 2 is a fragmentary sectional view on a larger scale showing thesupporting shroud for one row of vanes and the adjacent spacer ring.

Fig. 3 is a fragmentary sectional view showing a part of the shroud ringwith some of the vanes partially assembled.

Fig. 4 is a fragmentary sectional view at right angles to Fig. 3.

Fig. 5 is a view similar to Fig. 3, showing a further step.

Fig. 6 is a fragmentary sectional view similar to Fig. 4 with the outershroud ring assembled.

Fig. 7 is a fragmentary sectional view on a larger scale than Fig. 1,showing the diaphragm construction.

Fig. 8 is a fragmentary sectional view along line 8-8 of Fig. 7.

With reference first to Fig. 1 the invention is shown in a multistageaxial flow compressor in which a housing 2 is made up of a centralsubstantially cylindrical element 4 having stiffening ribs 6 thereon andend rings 6 and 8 bolted to the central element. The'housing supportsrows of axially spaced stator vanes 10 projecting inwardly from thehousing and alternating with rows of blades 12 on the rotor 14.

The rotor construction is not a part of the present invention. Theparticular rotor construction shown comprises a number of axially spaceddiscs 16 each having one row of blades 12 mounted on its periphery, thediscs being spaced apart by suitable spacer tubes 18 arranged in a ringaround the axis of the rotor. A surrounding cylinder 20 overlies thering of spacer tubes as shown. A number of through bolts 22 extendingthrough the series of discs and through the spacer tubes from one end ofthe rotor to the other secure the discs together in predetermined spacedrelation and also secure the end bells 24 and 26 which support the rotorin bearings, not shown.

Each of the rows of vanes 10 is supported at its outer end by a boxshroud 28 and carries at its inner end a diaphragm 30, the inner end ofwhich supports a sleeve 31 cooperating with sealing fins 32 on the outersurfaces of the cylinders 20 on the rotor. The box shrouds of successivevane rows are spaced apart by spacers 34 which function not only to holdthe box shrouds in predetermined spaced axial relation to each other butalso have projecting lugs 36 which pilot the spacer rings and boxshrouds within the outer housing. It will be noted that the element 4 ofthe outer housing has its inner surface formed as a succession ofstepped cylindrical surfaces 38 gradually increasing in diameter towardone end of the housing to provide for assembly of the housing over abuilt up assembly of stator rings and spacers.

As best shown in Fig. 2 each box shroud is made up of an innersubstantially flat ring 40 and an outer similar flat ring 42 throughboth of which the vanes 10 extend. The rings are spaced apart radiallyand are held in predetermined spaced relation by spacers 44 and 46welded or otherwise securely attached to the opposite edges of the rings40 and 42. The spacers 44 and 46 are preferably U-shaped, as indicated,to provide laterally open grooves 48 to receive cooperating tongues 50on the spacer rings 34.

Each of the spacer rings 34 has an inner surface 52 so spaced inreference to the tongues 50 that when the spacer rings and box shroudsare assembled the surface 52 on the spacer ring will form a continuationof the inner surfaces 54 of the adjacent box shrouds to provide a smoothsurface for the flow of the fluid being compressed.

The outer ring 42 and the adjacent portion of the spacers 44 and 46 arenotched as at 56 to receive the projecting lugs 36 on the spacer ringsthereby holding the box shrouds and spacer rings against relativerotation. It will be apparent that the lugs 36 are so dimensioned thatthey will provide a close fit with the cooperating cylindrical surface38 of the outer housing thereby functioning to pilot the spacer ringsand also the box shrouds accurately within the housing. It may be notedin connection with Fig. 1 that the endmost spacer ring 58 has aprojecting radial flange 60 which is engaged by the same bolts 62 thathold the main element 4 and end section 8 of the outer housing togetherthereby supporting this spacer ring in such a manner that it cannotrotate.

In the assembly of the stator vanes in the box shroud the entire row ofvanes are first punched through the inner ring 40, as best shown in Fig.4. In performing this punching operation the outer end of the bladeitself acts as the punch and the device is so set up that a suitableclamp 64 engages each blade and drives it through the ring 40, thelatter being backed up by a die 66 of conventional construction. It maybe advantageous'to'cut back the "trailing edge of the vane as shown at67, to improve the punching action.

The vanes having been punched through the inner ring 40, one of thespacers 44 or 46 is attached to the ring 40 and the outer ring 42 isattached to the spacer thereby "leaving the opposite edges of the rings40 and 42 open to permit the insertion of fingers 68 which space theinner "and outer rings and also support the inner ring'while with thevanes is'completed.

'With this arrangement, the holes in the rings 40 and 42 'are'inevitablyin precise radial alignment and of necessity accurately fit the vane,having been punched by the vane itself. Since the vanes remain inposition in the shroud 'rings'after the punching operation, they aresecurely held and supported by each of the inner and outer rings suchthat there is no looseness' and the only deflection that will occur whenthe row of vanes is loaded is the deflection resultingfrom the loaditself applied to the vanes rather than any deflection resulting fromlooseness between the parts.

At their inner ends, the vanes are supported in alignment with eachother by the diaphragm 30 which, to permit ease of assembly over theinner ends of the vanes, is madeup in two parts. One part 70 is in theform of a ring consisting of a disc or radial flange having at its outerperiphery a cylindrical or axially projecting flange 72. This flange isoffset at a point spaced from the disc by a dimension approximately halfof the axial dimension of the vane to form a shoulder 85 engaginglaterally with a radial surface 84 on the vane, as shown. The flange 72also has an outer surface 73 engaging -endwise with the vanes adjacentto their trailing edges (it will be understood that the row of vanes maybe notched at their inner ends after assembly in the outer shroud toprovide the precision surfaces engaged by surfaces 73 and 85). Thesecond part 75 of the diaphragm consists of a cylindrical portion orring 76 and a radial flange 78. The ring 76 has a row of notches 74,Fig. 8, corresponding approximately in shape to the upstream half of thecompressor vanes and is fitted over the inner ends of the vanes as bestshown in Fig. 8. The radial flange 78 abuts the surface of the radialflange on the part 70.

' As shown,.each vane has a notch 82 which substantially corresponds inshape to the surface of the flange 72 and is engaged thereby in theassembly of the parts. The notch 82 is preferably cut back adjacent tothe corner of the notch to provide two distinct surfaces for. engagementrespectively with the surfaces 73. and 85 on the 'flange 72. The vanesand the outer surface of the flange 72 have cooperating angled surfaces86 and 87 to provide a' wedging action when the parts 7 0. and 75 areassembled.

The second part 75 having been assembled in position it may be welded orotherwise secured to the disc 70. The inner end of radial flange 70 mayhave attached thereto a sleeve 31 which cooperates with the sealing fins32.

The stator ringhas been described with the sleeves and spacers for theouter shroud forming, when welded together, a shoud ring segment whichis a circumferentially unsplit part. It will be understood that the samepart may be made up of two or more ring segments each forming only apart of a complete circle but together forming a complete shroud ring.

In the assembly of the compressor, it has been found desirous in certaininstances to assemble. the rotor as a complete unit prior to itsassembly within .the stationary end of the rotor at the bottom. Thesplit halves of the stator-rings are thenplaced successively inposition. The

spacer rings 34 are not split and function to hold the stator rings inpredetermined relation around the rotor in such a manner that-the entireseries of stator vanes and box shrouds with the alternating spacer ringsmay be assembled around the rotor before the outer housing is placed inposition. Subsequently the housing is placed in position and the severalparts fastened together.

It is to be understood that the-invention is not limited to the'specificembodiment herein illustrated and described, but may be used in otherways without departure from its spirit as defined by the followingclaims.

I claim:

1. In the assembly of stator vanes in a supporting shroud, each vanebeing of substantially constant crosssectional shape'and dimension forthe length received in the shroud, the shroud consisting of inner andouter members in overlapping spaced relation, and spacer means securedto said members for holding said members in fixed spaced relation, thesteps of driving each vane through the spaced members to remove asection of shroud material to form the openings which receive the vane,supporting the members in said spaced relation while the vanes arepunched through the second of the two shrouds, and leaving each vane inthe members.

2. In the assembly of stator vanes in an outer supporting shroud, eachvane being of substantially constant cross-sectional shape and dimensionfor the length received in the shroud, the shroud consisting of innerand outer members in overlapping spaced relation, and spacer meanssecured to said members for holding said members in fixed spacedrelation, the steps of driving each vane through the spaced members toform the openings which receive the vane, supporting the members in saidspaced relation while the vanes are punched through the second of thetwo shrouds, leaving each vane in the members and subsequently securingthe inner ends of the vanes together.

3. In the assembly of stator vanes in the outer supportingshroud, eachvane being of substantially constant cross-sectional shape and dimensionfor the length received in the shroud, the shroud comprising inner andouter ring members in spaced concentric relation to each other, thesteps of driving each vane successively through the inner and outermembers such that each vane forms the openings which receive the'vane,'supporting the members in said spaced relation while the vanes arepunched through the second of the two shrouds, leaving each vane inthe'members, securing the members together to prevent relative axialmovement and subsequently securing the inner ends of the vanes together.

4. In the assembly of a number of closely spaced stator vanes in asubstantially cylindrical supporting shroud, the cross-sectional shapeand dimension of each vane being substantially constant for the portionof the vane received in the shroud, said shroud comprising inner andouter cylindrical members in overlapping and radially spaced relation'toeach other, with the vanes extending in a radial direction'with respectto the shroud, the steps of driving each vane successively through oneof said members such that the vane ends will punch through said one ofsaid members and project beyond the surface of said one of said members,subsequently supporting the members in predetermined spaced relation toeach other and driving each vane successively in a radial direction.throughthe other of said members While said members are supported inspaced relation such that the vane end will punch through the other ofsaid members and project beyond the surface of said other of saidmembers in the direction of the punching, and leaving each vane in theopenings thus formed in the inner and outer members.

5. In the assembly of a number of closely spaced stator vanes in asubstantially cylindrical supporting shroud the cross-sectional shapeand dimension of each vane being substantially constant for the portionof the vane received in the shroud, said shroud comprising inner andouter cylindrical members in overlapping and radially spaced relation toeach other, with the vanes extending in a radial direction with respectto the shroud, the steps of driving each vane successively through oneof said members such that the vane ends will punch though said one ofsaid members and project beyond the surface of said one of said members,subsequently supporting the members in predetermined spaced relation toeach other and driving each vane successively in a radial directionthrough the other of said members while said members are supported inspaced relation such that the vane end will punch through the other ofsaid members and project beyond the surface of said other of saidmembers in the direction of the punching, leaving each vane in theopenings thus formed in the inner and outer members and subsequentlysecuring the inner ends of the vanes together.

6. In the assembly of a number of closely spaced stator vanes in asubstantially cylindrical supporting shroud the cross-sectional shapeand dimension of each vane being substantially constant for the portionof the vane received in the shroud, said shroud comprising inner andouter cylindrical members in overlapping and radially spaced relation toeach other, with the vanes extending in a radial direction with respectto the shroud, the steps of punching an end of each vane through one ofthe members, supporting the members in predetermined spaced radialrelation and punching the same end of each vane through the othermember, said vane at the same time moving radially through said firstmember, leaving said vanes in said shroud members and securing saidmembers in fixed spaced relation to prevent relative axial movement.

7. In the assembly of a number of closely spaced stator vanes in asubstantially cylindrical supporting shroud the cross-sectional shapeand dimension of each vane being substantially constant for the portionof the vane received in the shroud, said shroud comprising inner andouter cylindrical members in overlapping and radially spaced relation toeach other, with the vanes extending in a radial direction with respectto the shroud, the steps of punching an end of each vane through one ofthe members, supporting the members in predetermined spaced radialrelation and punching the same end of each vane through the othermember, said vane at the same time moving radially through said firstmember, leaving said vanes in said shroud members and securing saidmembers in fixed spaced relation to prevent relative axial movement andsubsequently connecting the other ends of the vanes together.

References Cited in the file of this patent UNITED STATES PATENTS1,158,755 Weaver Nov. 2, 1915 2,120,711 Phillips June 14, 1938 2,278,040Allen Mar. 31, 1942 2,505,820 Zeidler May 2, 1950 2,593,506 Wales Apr.22, 1952 2,640,319 Wislicenus June 2, 1953 2,658,719 Johanson Nov. 10,1953 2,663,270 Friedly' Dec. 22, 1953 2,722,048 Gier Nov. 1, 1955

